Filter unit for fluids

ABSTRACT

A filter unit for fluids, the filter unit comprising a filter housing with at least one filter disposed therein, at least one fluid feed line, at least one purified fluid outlet line, and at least one unpurified fluid outlet line, each of which lines is provided with a valve. The filter is sealingly seated in the filter housing in an area between the fluid feed line and the purified fluid outlet line. The filter is in the form of a conical cylinder. The wide opening of the filter faces toward the fluid feed line and the underside of the filter forms a narrower opening sealingly disposed in an intermediate plate in the filter housing. A dirt funnel is disposed below the intermediate plate. A cleaning element is rotatably seated inside the filter housing which can be lowered into the filter from a filtration position into a cleaning position.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to a filter unit for fluids, said filter unit afilter housing and filters seated therein, at least one fluid feed line,one outlet line for the purified fluid and one outlet line forunpurified fluid, all of which are provided with valves.

2. Description of Prior Art

Filter units of this type have been commercially known for years.Included are the various filter structures for drinking water of KatadynProdukte AG in CH-8304 Wallisellen. A filter is known from DE-A-30 27997 which is equipped with a moveable brush. In these drinking waterfilters the actual filtration is performed with filter elements embodiedas hetero-capillary ceramic filters, and having a cylindrical shape. Thehollow-cylindrical filter is operated such that the unfiltered drinkingwater is disposed against the outside of the cylinder surface and flowsthrough the hetero-capillary cylinder wall into the hollow cylinder. Thehollow cylinder is filled with silver quartz granules and closed on thetop and bottom by a cap, wherein the lower cap has an outlet for thepurified drinking water. One or more such ceramic filter elements arefastened on an intermediate plate which is sealingly maintained in thefilter housing. Thus, the untreated water is located above thisintermediate plate and purified drinking water is located below it. Theuntreated water contains organic as well as inorganic impurities, whichsettle on the surface of the ceramic filter element during filtration.So that the filter elements do not become clogged and so that no climatefor extreme bacterial growth is created, it is necessary to clean theindividual filter elements in regular timed intervals. To do this, it isnecessary to stop the filtration operation and hand clean eachindividual filter element. Accordingly, such drinking water filters areprovided with a separate, hydraulically operated cleaning brush mountedon a flexible tube outside the filter housing. When the filter housingis open, the brush is manually placed over each filter element andbrushing and rinsing is then performed. Depending on the size of thedrinking water filter, it may be necessary to clean up to fiftyindividual filter elements. This is normally done during normal workinghours and therefore leads to corresponding breaks in operation inrestaurants, hotels and bottling plants.

The same problems also apply to other fluids. Thus, this invention isnot limited to drinking water filtration. Although the structure isdescribed as a drinking water filtration installation in the followingdescription, it can also be utilized without modifications for otherfluids.

SUMMARY OF THE INVENTION

Accordingly, it is an object of this invention to provide a drinkingwater filtration unit which permits a simple cleaning while inoperation.

This and other objects of this invention are achieved by a filter unitcomprising a filter housing and at least one filter seated therein, atleast one fluid feed line, one purified fluid outlet line and oneunpurified fluid outlet line, each of said lines being provided with avalve. The filter is sealingly seated in the housing in the area betweenthe fluid feed line and the purified fluid outlet line. The shape of thefilter is a conical cylinder, the wide end of which faces the fluid feedline, while the underside with the narrower opening sealingly rests inan intermediate plate in the filter housing. A dirt funnel with anoutlet line for untreated fluid is disposed below the intermediateplate. A cleaning element is rotatably seated inside the filter housingand can be lowered inside the conical filter from a filtration positionto a cleaning position.

In accordance with one embodiment, purely manual function is providedfor use particularly in remote areas and third world countries, where adependable electrical supply is not assured.

In accordance with another embodiment of the invention fully automaticoperation, which permits a purely time-controlled cleaning is provided.

BRIEF DESCRIPTION OF THE DRAWING

These and other features of this invention will be better understoodfrom the following detailed description taken in conjunction with thedrawings wherein:

FIG. 1 is a longitudinal section through a filter unit for fluids withautomatic cleaning in accordance with one embodiment of this invention;

FIG. 2 is a partial section of the drive section of a filter unit inaccordance with one embodiment of this invention, which is intended formanual operation; and

FIG. 3 is a partial section of the filter unit in the drive section,which can be actuated by the exerted pressure of a fluid, but operateswithout a turbine.

DESCRIPTION OF PREFERRED EMBODIMENTS

A filter unit with a single filter is shown in the drawings. It is ofcourse possible using the same principle shown in the drawings toprovide filter units with any arbitrary number of ceramic filtersdesigned in the same way. The filter unit for fluids is described indetail in the following description using a filter unit for drinkingwater as the example.

The size of the drinking water filter unit is determined by the filterhousing 1. It is of course possible for several filters to be disposedin the housing. The general design is the same. The filter can be aceramic filter, a hetero-capillary ceramic filter or any other filter ofa relatively solid material. Thus, reference to ceramic filters in thisdescription only represents a preferred form without being limited toit. The filter housing, which can have any arbitrary shape, is dividedinto different zones by several generally horizontally extending plates.In the area of a flange 6, the entire filter housing 1 is divided intoan upper part and a lower part. At the top, the filter housing 1 can beprovided with a pivotable cover 2, which provides free access to acontrol zone. At the bottom, the control zone is bounded by a coverplate 3. The drive zone 4 is located below the cover plate 3 and in turnis bounded toward the bottom by a support plate 5. The actual filtrationzone 8 is located below the support plate 5, in which the filter 7 isarranged. The filter 7 rests at its upper edge area on a filter support16, and at its lower area on an intermediate plate 9. The filter 7 issealingly maintained in both the filter support 16 and the intermediateplate 9. The drain area 17, in which a funnel 10 for dirty water isdisposed, is disposed below the intermediate plate 9. The dirty waterfunnel 10 terminates in a dirty water outlet 18 at the lower end of thefilter housing 1. The dirty water outlet 18 is opened and closed by adirty water closing valve 15. Depending on its design, this valve can beembodied to be manually or electrically actuable.

The ceramic filter 7 has the shape of a conical cylinder and inaccordance with one embodiment is made of hetero-capillary ceramicmaterial. To increase its sturdiness, the ceramic filter can bereinforced by means of a metal or plastic net. In the area between theceramic filter and the wall surface of the filter housing 1, thefiltration zone 8 is filled with an anti-bacterial agent, for examplesilver quartz granules, between the filter support 10 and theintermediate plate 9. The silver quartz granules are introduced into thefilter housing 1 through the filler neck 19. The untreated water to bepurified is introduced into the drive zone 4 through the untreated waterconnector 11 and from there is introduced through a mechanically orelectrically controllable reversing valve into the filtration zone 8. Inthis case, the dirty water closing valve 15 is closed and the inflowinguntreated water fills the dirty water funnel 10 as well as the conicalcylinder of the filter 7 at most up to the area just below the supportplate 5. The untreated water is disposed against the inner wall surfaceof the filter 7 and penetrates the filter 7 until it reaches the areabetween the ceramic filter and the filter housing. From this area, itcan flow out through the drinking water outlet 13 as purified drinkingwater. The drinking water outlet 13 is provided with a closing valve 14,which can be manually or electrically actuated. If the closing valve 14is electrically actuable, it can also be disposed inside the filterhousing. It is, of course, also possible to dispose the closing valve 14outside of the filter housing 1. In a particularly simple embodiment ofthe drinking water filter, the untreated water connector 11 isintroduced into the filtration zone 8 directly underneath the supportplate 5 and above the filter support 16. In this case, the reversingvalve 12 is omitted and a simple closing valve attached outside of thefilter housing 1.

Because the filter 7 is used here in such a way that the untreated wateris disposed against the interior surface of the conical cylinder,organic and inorganic dirt particles will correspondingly be depositedthere, too. A cylindrical brush 20 is accordingly, thus, in the filterhousing 1, whose central rotational shaft 21 passes through the supportplate 5 and is rotatably held in a bearing 22. The shape of thecone-shaped brush 20 is such that it can be exactly received in theconical cylinder shape of the ceramic filter 7. So that the brush doesnot continuously rest on the filter 7 and thus affect its function, thebrush 22 is held, movable in the axial direction, in the bearing 22 andin the support plate 5. In the filtration position, the brush 20 is inan upper position in which it does not come into contact with theceramic filter, while the brush is moved downward in a cleaning positionso that it comes into intimate contact with the filter 7. In thisposition, the brush is rotated. This can occur in a simple manner eithermanually (see FIG. 2) or, as represented in FIG. 1, by means of theapplied water pressure.

In accordance with the embodiment shown in FIG. 1, the brush 20 ismaintained in an upper position, the filtration position, by a spring 34which acts on shaft 21. Spring 24 is designed as a tension spring or, ina known force reversing construction, as a pressure spring. When thebrush 20 is to be brought into the cleaning position, the lowerposition, the reversing valve 12 is reversed so that, on the one hand,the prevailing water pressure above the rotational shaft 21 pressesthereon and brings the brush 20 into the cleaning position against theforce of the spring 24. To this end, the drive shaft 21 is seated in aclosed bushing used as a hydraulic cylinder 23. Thus, it is assured, dueto a controlled leak between the hydraulic cylinder 23 and the driveshaft 21 acting as a piston, that, with the pressure removed at the endof the cleaning process and correspondingly by reversing the reversingvalve 12, the water can escape from the hydraulic cylinder 23 under theeffect of the spring 24 and the brush again reaches the upper filtrationposition. The main stream of the untreated water is guided through thereversing valve 12 on a water turbine 25, whose symbolically representedoutlet 28 guides the untreated water through the support plate 5 intothe filtration zone 8. The cleaning brush 20 now rotates, scrubbing theimpurities off the inner wall of the surface of the ceramic filter 7,while simultaneously the water flowing out of the water turbine 25flushes these impurities away, during which they reach the dirty waterfunnel 10 below the intermediate plate 9. The dirty water valve 15 is ofcourse opened during this time, so that the dirty untreated water canflow off. During this cleaning process, the drinking water outlet 13 canin principle remain open, because the filtration function is notqualitatively affected even during the cleaning process. However, duringthe cleaning process a portion of the purified drinking water will flowfrom the area between the outer wall surface of the filter 7 and thefilter housing 1 in the reverse direction through the filter andpartially empty it. To prevent air from reaching the downstream drinkingwater pressure lines, the closing valve 14 can be closed. The closing ofthe valve 14 can be controlled by a water level sensor, for example.

When the cleaning process is completed, for example, after approximatelytwo to three minutes, the reversing valve 12 is turned back into thefiltration position and the untreated water again reaches the filtrationzone directly. Simultaneously, the spring 24 pulls the brush 20 backinto the filtration position and the dirty water closing valve 15 isclosed. If the closing valve 14 has been closed during the cleaningprocess, it is also opened again. The cleaning cycle is thus completed.

The cleaning process can be automated to prevent interruptions in theoperation, to which end an electric control 26 is disposed under thecover 2 on the cover plate 3, which automatically controls the process,for example through an integrated or external circuit. In accordancewith this embodiment, the valves 12, 14 and 15 are electricallyactuable. The electrical supply and possibly a transformer areaccordingly housed in a water-tight and insulated box 27.

In remote areas with unreliable supply of electrical power, it may bedesirable to offer a solution which is manually operated to a largedegree or completely. This is easily possible with the embodiment inaccordance with the invention in that the various valves can be manuallyoperated. In this case, too, the two movements of the brush are actuatedby the prevailing water pressure. However, if the degree of purity ofthe untreated water is very low, it is possible that a solutionemploying the water pressure can be prone to trouble. In this case, themovements of the cleaning brush 20 are also performed manually. Thisembodiment is shown in FIG. 2 in a partial section only in regards tothe actuation. The filter housing 1 is represented in a sectional view,wherein only a portion of the filtration zone 8 and the drive zone 4 canbe seen. The cover 2 is represented in the flipped open state. Asalready mentioned, the untreated water connector 11 is directlyintroduced into the filtration zone 8. In place of the reversing valve12 of the drive zone 4, a simple, manually operable closing valve 110 isused, which is disposed outside of the filter housing 1. The drive shaft21 of the cleaning brush 20, which dips into the filter 7, passesthrough the support plate 5, on the underside of which a bearing 32 isdisposed. A carrier bolt 29 passes through the rotational shaft 21 andextends radially from the rotational shaft 21. This carrier bolt 29engages a guideway in the bearing 32. The guideway is divided into threesectors, namely an upper, circular-shaped track 34, a lower,circular-shaped track 35 and a helically wound track 33, which connectsthe two circular tracks 34 and 35 to each other. A spring 24 is providedwhich pushes the cleaning brush 20 into an upper filtration position.The spring 24, which here is embodied as a pressure spring, restsdirectly on the support plate 5 and presses against a collar 36, whichis fixedly connected with the drive shaft 21. At the upper end, thedrive shaft 21 is provided with a square or hexagon socket 30, forexample, into which a hand crank 31 can be inserted. If pressure is puton the crank and it is simultaneously turned counterclockwise, thecarrier bolt 29 in the corresponding angular position is pushed into thehelical guideway and turns as far down as the lower cleaning position,wherein the carrier bolt 29 then runs in the lower circular guidesurface 35, while the pressure spring 24 is tensed and the brush 20rests on the filter 7. If after some revolutions the ceramic filter 7 issufficiently cleaned, it is only necessary to change the direction ofrotation of the crank 31, wherein the spring 24 again presses thecarrier bolt 29 into the helical guideway 33 when the correspondingangular position has been reached and from there is screwed upward untilit again extends in the upper ring-shaped guideway 34. Followingcleaning, the crank 31 can be removed and placed on the support plate 5,after which the cover 2 can be closed. The remaining valves, notillustrated here, can be opened and closed in an absolutely analogousmanner as in the automated version.

Brush actuation in accordance with another embodiment of this inventionis shown in FIG. 3. The unpurified liquid, for example, the untreatedwater, is supplied to the filter unit through a valve, not shown,directly through the feed line 11 or through an actuating line connector11'.

Here, too, the brush 7 is moved up and down in a translatory manner andmade to rotate. During normal filter operations, the fluid to bepurified is supplied through the line 11 and flows into the cylinder 42which is emptied at the bottom through a pressure control valve 43. Apiston 44 which is acted upon on both sides is movably seated in thecylinder. During filter operation, the piston 44 in the cylinder 42 ispushed upward. The direction of the flow is represented by solid arrows.After the water has passed through the pressure control valve 43, thefurther process corresponds to the one described so far.

However, if the water pressure is moved to the connector 11', a controlpiston 45 which extends parallel with the actuation cylinder 42, ismoved downward in a control cylinder 46. It therefore opens theactuation line 47 and the fluid flows in the area above the piston 44,as shown by dashed lines.

The piston 44 is pushed downward, the water below the piston is emptiedthrough the pressure control valve 43 and the drive shaft 21, which isseated in the piston 44, is moved downward and simultaneously caused torotate by means of the screw thread 40. So that cleaning takes placeduring the downward movement already, the drive shaft 21 is embodied tobe secure against twisting within itself and telescopic.

When the piston 44 has been completely pushed down, the brush 20 isstationary and the fluid cannot flow out unnecessarily. When thepressure of the liquid is again applied through the line 11, the controlpiston 45 is moved upward. The piston 44 is pressed upward by theinflowing fluid, while the fluid present above the piston 44 can flowout through the pressure control line 48 because the control piston 45now releases this passage. Accordingly, the feed lines 11 and 11' aretherefore alternatingly controlled for cleaning in order to achieve thedesired cleaning effect.

The basic principle of the invention particularly rests in the conicalshape of the filter, as a result of which the cleaning brush 20 can bemoved from an inactive filtration position over a small stroke path intoan active cleaning position. Another condition of course is that thefilter be open at the bottom, so that the dirt particles can be removedat the bottom. This has the additional advantage that larger, slightlyheavier dirt particles do not remain in the filter area during thefiltration process.

I claim:
 1. In a filter unit for fluids, said filter unit comprising afilter housing (1) and at least one filter (7) seated therein, at leastone fluid feed line (11), at least one purified fluid outlet line (12,14, 15) and at least one unpurified fluid outlet line (13, 18), each ofwhich is provided with a valve, the improvement comprising; the filter(7) sealingly seated in the filter housing (1) in an area (8) betweenthe at least one fluid feed line (11) and the at least one purifiedfluid outlet line and having a conical shape, a wide opening of saidconical filter facing the at least one fluid feed line, an underside ofsaid conical filter with a narrower opening sealingly disposed in anintermediate plate in the filter housing (1), a dirt funnel (10) withthe at least one unpurified fluid outlet line (18) disposed below saidintermediate plate (9), and a cleaning element (20) rotatably mountedinside the filter housing (1), means for rotating said cleaning elementand means for moving the cleaning element from a filtration position inwhich the cleaning element does not engage the conical filter to asecond cleaning position in which the cleaning element engages theconical filter.
 2. A filter unit in accordance with claim 1, wherein themeans for moving comprises manually operable means for moving thecleaning element from the filtration position into the cleaning positionagainst a force of a spring and said means for rotating comprises acrank (31).
 3. A filter unit in accordance with claim 1, wherein thecleaning element is sealing seated in a support plate (5) above theconical filter (7).
 4. A filter unit in accordance with claim 3, whereina bearing (32) of the cleaning element (20) forms a helical crank guide(33), out of which the cleaning element (20) can be returned by turningin one direction into a lower cleaning position and by turning anopposite direction into the filtration position by a spring force.
 5. Afilter unit in accordance with claim 1, wherein the means for movingcomprises hydraulic means driven by the prevailing pressure of the fluidto be purified.
 6. A filter unit in accordance with claim 1, wherein acontrollable reversing valve (12) is disposed inside the filter housing(1) in the fluid feed line (11) by which in the filtration position thefluid is directly introduced into the filter (7), while in the cleaningposition of the reversing valve (12), the unpurified fluid is routedover a hydraulic turbine (25), which rotatingly drives the cleaningelement.
 7. A filter unit in accordance with claim 6, wherein thereversing valve (12) guides the pressure of the fluid to be purified toa piston cylinder (23) disposed above a rotary shaft (21) of thecleaning element (20), which pushes the cleaning brush (20) into thefilter (7) from the filtration position into the cleaning position.
 8. Afilter unit in accordance with claim 1, wherein the valves (12, 14, 15)are electrically controlled.
 9. A filter unit in accordance with claim1, wherein the intermediate plate (9) in the filter housing (1) isremovably seated.
 10. A filter unit in accordance with claim 1, whereinthe pressure of the fluid to be purified can be selectively directed tothe at least one fluid feed line (11) or an actuating connector (11'),through which the fluid is present above or below a piston (34) andmoves said piston (34) up and down, along with the cleaning element (20)indirectly fastened on it.
 11. A filter unit in accordance with claim10, wherein the cleaning element (20) is seated on a telescopic shaft(21), which is secure against twisting, and has an exterior screw thread(40) and can be scanned and thus puts the brush into rotary movementduring the downward movement.